Confused? Me too!
If you apply for a job online (one of many strategies--should not be your only one!), be aware that your material may be scanned by a software package purchased by your target employer. Why? So that some poor schmo in HR doesn't have to spend days on end manually sifting through hundreds of pieces of paper to short-list job applicants... just for one position.
What does that mean for you? That even if you are the objectively perfect candidate for a job, your materials may well get tossed in the trash because you did not format or phrase stuff the exact way the computer wanted to hear it said.
Maybe this means that in addition to having one resume tailored for each job, you might want to have a second version tailored for the computer (if your first is tailored for human eyes).
- An overview of perils and pitfalls of ATS: http://40pluscareerguru.blogspot.com/2014/07/applicant-tracking-systems-hidden-peril.html (Thanks @SuttonJobsPlus)
- A step-by-step list of ways to optimize for ATS: http://mashable.com/2012/05/27/resume-tracking-systems/ (Thanks @JCPForthValley)
- A cluster of articles which will help you refine your strategy: http://www.quintcareers.com/Content-Index/Applicant-Tracking-System.html (Thanks @careersherpa!)